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A microfiche appendix containing program source code used in one embodiment of the invention schematic diagrams of one embodiment of a circuit employed in data capture is submitted herewith. The microfiche comprises 5 fiches and 267 frames.
1. Field of the Invention
The present invention relates to locating systems and, more specifically, to a system for scoring projectiles fired at a target.
2. Description of the Prior Art
Current small arms scoring systems use various techniques to measure impact coordinates and velocity information relating to small arms projectiles. With the acoustic technique, acoustic targets measure a shock wave produced by a high speed projectile. By measuring the time of acoustic impact at the four corners of a target, accurate change locations may be obtained. This technique has a disadvantage in that it is sensitive to environmental changes such as changes in temperature, pressure and humidity. This technique also does not work with sub-sonic projectiles.
The impact spark technique relies on having a material in the target area that facilitates optical detection of impact points. This technique has the disadvantage of being difficult to operate outside due to ambient light.
The high speed charge coupled device (CCD) imaging technique images a target area and detects scattered light reflected off of a projectile using a CCD camera. This technique has a disadvantage in that different projectile surface types lead to different inconsistency in light reflection.
Therefore, there is a need for a target scoring system that is immune to environmental changes and that is accurate irrespective of such variables as ambient light and projectile surface type.
The disadvantages of the prior art are overcome by the present invention which, in one aspect, is a device for target scoring that includes an elongated retro-reflective member, a first light source, a second light source, a first light sensor, a second light sensor and a processor. The first light source is disposed at a first location and is spaced apart from the retro-reflective member. The first light source is also positioned so as to be able to direct a first beam of light toward the retro-reflective member. The second light source is disposed at a second location spaced apart from both the retro-reflective member and from the first light source. The second light source is also positioned so as to be able to direct a second beam of light toward the retro-reflective member so that the second beam of light intersects the first beam of light over an area so as to define a target area. The first light sensor is disposed adjacent the first light source and is positioned so as to be able to receive light from the first light source that has been reflected from the retro-reflective member. The first light sensor generates a first signal indicative of a first position of a first object sensed by blockage of illumination from the retro-reflective member. The second light sensor is disposed adjacent the second light source and is positioned so as to be able to receive light from the second light source that has been reflected from the retro-reflective member. The second light sensor generates a second signal indicative of a second position of a second object sensed by blockage of illumination from the retro-reflective member. The processor is responsive the first signal and to the second signal and is programmed to determine a location of the object in the target area, based on the first position of the first shadow and the second position of the second shadow.
In another aspect, the invention is a device for target scoring that includes an elongated lamp having a first end and a second end. A first light sensor is spaced apart from the elongated lamp and is disposed so as to be able to receive light from every point along a first portion of the elongated lamp. The first light sensor is also capable of detecting a blockage of light from a second portion of the elongated lamp. The first light sensor generates a first signal indicative of an angular position of the blockage relative to a predetermined axis. A second light sensor is spaced apart from the elongated lamp and from the first light sensor. The second light sensor is disposed so as to be able to receive light from every point along the first portion of the elongated lamp and is capable of detecting the blockage of light from the second portion of the elongated lamp. The second light sensor generates a second signal indicative of an angular position of the blockage relative to the predetermined axis. A processor that is responsive the first signal and to the second signal is programmed to determine a location of the object, based on the angular position of the blockage.
In yet another aspect, the invention is a method of determining a location of an object. A first beam of light from a first light source is directed toward a retro-reflective member. A second beam of light from a second light source is directed toward the retro-reflective member. A position of a first shadow cast by the object onto the retro-reflective member as it is illuminated by the first beam is determined. A position of a second shadow cast by the object onto the retro-reflective member as it is illuminated by the second beam is determined. The location of the object is determined by determining the point where a line from the first light source to the first shadow intersects a line from the second light source to the second shadow.